a few questions

Emilee · Nov 10, 2009

Hi, I've been making cp soap for 2 years, and now having a play with skin cream and lotion.

questions:

there are so many different emulsifiers. Can someone explain why? I understand the basics, but is it just like there are many different oils and each one has a different composition and is for a different purpose?

Also, I use the soapmaking program soapmaker. Does anyone know of a skin cream/lotion program/formulator?

Are there general % formulas for the 3-4 phases of the formula eg 3 parts water to 1 part oil to 1/2 emulsfier? or something like that?

I've visited heaps of skin cream/lotion making websites and looked at their formulas and recipes, but each one uses a different emulsifier, and I'm not sure how to pick one. I've bought 4 already and had a play around a little bit, but just wanting some more info from experienced people if poss.

Thanks

Absinthe · Nov 11, 2009

I am probably not the correct person to answer this question but, why should that stop me. Hopefully, someone will correct me if I am wrong.

The reason you use an emulsifier at all is because oil and water don't mix. If you have ever made your own salad dressing you are well aware of this fact, and when you shake it up and pour it on the salad then set it down it eventually breaks apart again and layers out into oil and vinegar.

Waxes and other emulsifiers on the molecular level are "shaped" in such a way that they can hold onto fat molecules with one hand, and water molecules with the other hand. Though that may be a bad metaphor, most of the other ones coming to mind might not work in mixed company

As for how much to use, what you are looking for is an HLB. There are tables, that give a HLB value for each oil-emulsifier relationship. Sometimes you will have to use multiple emulsifiers because one may work fine with one oil but not another that you are using. If you use emulsifying wax, it is a combination of several which tries to be all things to all oils

Sometimes it fails at that

I have not found a really good reference like SoapCalc, or those lye calculators, but having the data (which does exist) it would not be all that difficult to write one either as a web page or an excel spreadsheet. The exception to that statement is, in this case you are trying to calculate more than just "how much lye" as in "How much emulsifier." Depending on the oils, you may have to calculate "which emulsifier" or "choose one of the following" and then how much, and which other emulsifier and so on. So it is a more involved final calculation.

Here are some links that might get started:

http://pharmcal.tripod.com/ch17.htm
http://www.snowdriftfarm.com/what_is_hlb.html (seems like the table is missing though

)
http://www.theherbarie.com/files/resour ... Lipids.pdf
http://www.specialchem4cosmetics.com/se ... px?id=1928
http://www.crodalubricants.com/download ... doc&id=267
http://www.lotioncrafter.com/pdf/The_HLB_System.pdf
http://class.fst.ohio-state.edu/fst621/ ... ifiers.ppt

Deda · Nov 11, 2009

Absinthe is right about the HLB Scale.

Your choice of which emulsifier to use should be based on trial and error. I think I tested 10 to 12 different combinations until I found a couple that I like the feel of and was satisfied with long term results.

Reading all you can is great, but it won't beat actually testing. It's kinda what formulating is all about.

Buy a few ounces of the ones that interest you, start testing, keep track, make notes.

Don't forget to the preservative system, you'll want to test that along with the emulsification. When you find the right formula you should submit the whole thing for challenge testing.